Abstract

Kinetics of oxidation of malic acid by benzyltrimethylammonium fluorochromate (BTMAFC) in acetonitrile-water solvent mixture at 298 K in the presence of perchloric acid has been followed spectrophotometrically. The reaction is first order with respect to both malic acid and BTMAFC and is catalyzed by H+ ion. Hydrogen ion dependence shows the form kobs = a + b[H+]. The reaction rate is not affected by changes in ionic strength of the reaction medium or by the addition of acrylonitrile. However, addition of manganese sulphate causes a decrease in the rate of reaction. An increase in the water content of the solvent mixture decreases the rate of reaction. The reaction has been studied at four different temperatures and activation parameters, ΔH‡, ΔS‡ and ΔG‡ have been evaluated using Arrhenius and Eyring equations. Based on these findings, a suitable mechanism involving a direct hydride ion transfer from substrate to oxidant has been proposed